Prairie Ecosystems: There is More Than Meets the Eye

Posted by: Lisa Mason, Arapahoe County Extension

This past week, I co-taught my first Native Plant Master course at the Plains Conservation Center. We completed the first of three sessions. It was a wonderful experience learning and teaching in such a beautiful setting.

When I was in the third grade, I went on a Girl Scout field trip to the Plains Conservation Center. I remember the day vividly. Upon arriving there were no trees in sight, just dry, brown grassy fields. Then we started to explore. We saw lady bugs and lady bug eggs, raptors, butterflies, pronghorn, flowers, the tipi camp, homestead village, and the wildlife displays in the visitor center. The message I took home that day: there is more to the Plains Conservation Center than meets the eye! There is an ecosystem full of life and diversity on the prairie. I have always had an appreciation for prairie ecosystems after that field trip.

Fast forward many years: I returned to the PCC to learn and share my knowledge and appreciation of prairie ecosystems by co-teaching the Native Plant Master course. The PCC did not disappoint! Here are a few highlights:

A bee fly, Bombyliidae family on a sunflower, Helianthus annuus. Photo: Lisa Mason

Blue grama, Bouteloua gracilis, the state grass of Colorado. Photo: Lisa Mason

Milkweed and Specialist Relationships

Showy milkweed (Asclepias speciosa) is a common native plant found at the PCC. Milkweed tends to be a popular plant for pollinators because of the available nectar, but milkweed also hosts two specialist insects. A specialist insect depends on a certain environment or food source compared to a generalist that can survive in a more variable environment with diverse food sources. Monarch butterflies (Danaus plexippus) are specialists of milkweed because the caterpillars rely solely on milkweed for their diet. Milkweed contains toxins that are poisonous to predators such as birds but not poisonous to the monarch thus protecting the caterpillars and butterflies from predators.

Milkweed longhorn beetles (Tetraopes spp.) also have a specialist relationship with milkweed plants. The beetles spend their entire lives on milkweed plants. Many species will lay their eggs at the root crown. The larvae develop on the roots, some living in the soil feeding on small, young roots and others tunneling in the large taproot of the milkweed. They pupate in the soil and the adults spend most of their time above ground feeding and mating on the plant. (Source: CSU Extension)

Milkweed longhorn beetle, Tetraopes femoratus. Photo: Lisa Mason

Rabbitbrush and Generalist Visitors

Rabbitbrush (Ericameria nauseosa) is also a common native plant at PCC and blooms late in the season. This plant is a fantastic food source for a variety of generalist insects including bees, wasps, flies, and beetles. I encourage you to observe rabbitbrush this time of year and notice the diversity of insects buzzing and crawling around the plant. Rabbitbrush can also be an important forage source for other animals, including pronghorn, commonly seen at the PCC.

Soldier beetle, Chauliognathus pennsylvanicus on rabbitbrush. Photo: Lisa Mason

Swainson’s Hawks and Other Raptors

Birds of prey or raptors are defined by their sharp talons they use to hunt and kill prey. Common raptors seen at PCC include Swainson’s hawks, red-tailed hawks, great horned owls, burrowing owls, eagles, turkey vultures, American kestrels and more. We were lucky to see a pair of great horned owls, a red-tailed hawk, a Swainson’s hawk and a bald eagle nest. With the season changing to autumn, the Swainson’s hawks are starting to gather into groups, or kettles on the Eastern Plains. They are eating as much as possible right now so they can migrate to Argentina for the winter.  They migrate north in the spring and many spend their summers in Colorado.

Swainson's hawk, Buteo swainsoni. Photo: Steven Mlodinow, Macaulay Library, Cornell Lab of Ornithology 

Pronghorn

Many people see pronghorns (Antilocapra americana) on the prairie and don’t think too much about it, but pronghorns are fascinating animals!  First, they are the fastest land mammal in North America and second fastest in the world! They can run at up to sustained speeds of 60 mph. They have incredible vision and a keen sense of smell. Their vision is comparable to a human looking through 8x-power binoculars.

You might associate pronghorn with deer or even mountain goats, but they aren’t related to either. They are in a family of their own called Antilocpridae and are the only living species in the family. The closest living relatives of pronghorn are actually giraffes. (Source: University of Wyoming Extension and University of Wisconsin at Stevens Point)

Pronghorn, Antilocapra americana. Photo: Lisa Mason

Visit the Prairie

Next time you are at the PCC or any other prairie ecosystem, I encourage you to look closer and observe many of the fascinating plants and animal relationships and adaptations. There is more than meets the eye.

A view at the Plains Conservation Center. Notice the colors and textures. How many different types of plants do you see? Photo: Lisa Mason

The PCC is managed by the City of Aurora and the Denver Botanic Gardens. Click here for more information on visiting the PCC.

If you are interested in taking classes through the Native Plant Master program, click here.